Laravel 5.2验证检查值是否不等于变量

In my instance one user is inviting another I would like to check if the user they are inviting is not themselves.

Thus I have two variables incomming email and user->email

$this->validate($request, [
            'email' => 'required|email',
        ]);

How can I add that validation rule to the validation call?

You can use not_in, which allows you to specify a list of values to reject:

$this->validate($request, [
    'email' => 'required|email|not_in:'.$user->email,
]);

You can use different:field according to the laravel Document

For instanse in your requests validation:

public function rules()
    {
        return [
            'from' => 'required',
            'to' => 'required|different:from',
            'action' => 'required',
            'access' => 'required'
        ];
    }

These two from and to should be different(not same).